Margolis is the current day champion of the ancient Protagoras in that he takes the latter’s dictum “Man the Measure” to its logical conclusions, showing how, strictly adhering to such a measure, all fixities and changeless first principles must give way to consensual, though not criterial, truth claims. Since “man”, the measure, is himself a creature of history, no modal claims of invariance can possibly be sustained. Margolis however avers that there need be no fixities either de re or de dicto or de cogitatione. The world is a flux and our thought about it is also in flux. Margolis sees the whole history of Western Philosophy as a struggle between the advocates of change and those who either, like Parmenides, deny that change is intelligible at all, or those, like Heraclitus, who find some logos or some law which allegedly governs whatever changes are admitted. Contrary to “postmodern” philosophers like Richard Rorty or Jean-François Lyotard, he shows that our lacking cognitive privilege means that the need for a philosophical justification of our choices and programs becomes more, not less, pressing now than at any previous time.